Boom arm



FIG. 1 is a top rear right side view of a boom arm showing our new design;

FIG. 2 is a top rear view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a rear view thereof;

FIG. 7 is a top plan view thereof;

FIG. 8 is a front view thereof;

FIG. 9 is a top front perspective view thereof;

FIG. 10 is another right side view thereof;

FIG. 11 is another left side view thereof;

FIG. 12 is another bottom plan view thereof;

FIG. 13 is another rear view thereof;

FIG. 14 is another top plan view thereof; and,

FIG. 15 is another front view thereof.

The figures are not necessarily shown in scale with each other in order to show clarity of line and detail for each view. The broken line representations in the figures define the bounds of the claimed design and form no part of the claimed design. 

The ornamental design for a boom arm, as shown and described. 